Door lock hardware



Dec. 12, 1967 s. T. HEIFETZ DOOR LOCK HARDWARE 2 Sheets-Sheet .l

Filed sept. 22, 1964 INVENTOR S'fbgey 7.' fie/fe?? TTORNEY Dec. 12, 1967s, T, ||E|FETZ 3,357,733

DOOR LOCK HARDWARE Filed Sept. 22, 1964 2 Sheets-Sheet 2 Hm@ a:

United States Patent Olltice 3,357,733 Patented Dec. 12, 1967 3,357,733DUUR LOCK HARDWARE Sidney T. Heifetz, New York, NSY., assignor toHeifetz Metal Crafts, lne., Wood Ridge, NJ., a corporation of New JerseyFiled Sept. 22, 1964, Ser. No. 398,309 4 tlaims. (Cl. 292-465) Thisinvention relates to improvements in door lock hardware and particularlyto flush type manually-operable door-pull mechanisms for hinged,bolt-locked doors.

Still more particularly, this invention relates to a combinationdoor-pull and latch bolt mechanism of the above character, the manualengageable element is of the recessgrip type, only the fingertips areemployable in the recess, and wherein, pulling intent is by fingertip,in the normal and natural procedural requirement for opening the door.

One of the principal objects of the invention is the provision of suchabove mentioned door-unbolting and door-opening mechanism, of highsimplicity in construction and appearance, having no protuberances orforward projecting or projectable parts, no moving parts in or withinthe recess, and requiring -a minimum of manual action and effort in itsoperation including an involuntary effort resulting in au unintentionalelfect in the course of opening events.

Another object of the invention is the provision of a piece of doorhardware of the above character wherein only one single unitary part ofthe mechanism is visibly available for operation, and which is manuallycontactahle for pulling engagement when the door is closed.

Still another object of the invention is the provision of a flush typelatchable-bolt door-pull mechanism that is of highly sanitaryconstruction, ellicient in use, with a minimum of parts, and inexpensiveto manufacture and install.

Further objects and Iadvantages will be pointed out and still otherswill appear in the following description having reference to theaccompanying drawings illustrating a preferred form and modifications ofthe invention.

In the drawings:

FIG. 1 is a front perspective view of a portion of a cabinet havingdoors provided with hardware of one principal form of the invention.

FIG. 2 is an enlarged front view of a portion of the structure shown inPG. l.

FIG. 3 is an enlarged section on the line 3-3 of FiG. 2.

FIG. 4 is an enlarged view on the line 4-4 of FIG. 3.

FIG. 5 is a rear view of the parts shown in FIG. 2.

FIG. 6 is a view similar to FIG. 5 but with the parts shown in anintermediate position, in the course of opening the door.

FIG. 7 is a perspective View of a bolt cage used in this form of theinvention.

FIG. 8 is a perspective view of a particular bell-crank part employed inthe above form of the invention.

v FIG. 9 is a view-similar to FIG. 5 but of another form of theinvention.

FIG. l0 is a section taken on the line 1li-lil of FIG. 9.

FIG. l1 is a view similar to FIG. 5 but of still another form of theinvention.

FIG. l2 is a sectional view on the line 12-12 of FIG, 11.

In flush type door-handle devices having manually en- `gaging andmanipulative operating requirements, the action and efforts required toopen the door are generally suggested by the nature and appearance ofthe manually engageable parts of the particular device. Its physicalpresentments, the nature of its appurtenances, the size, orientation anddisposition of its protuberances or recesses all influence thedetermination of the nature of manual contact, by linger or hand, andinfluence the manner of procedural action and efforts required of oneabout to open the door.

In the present invention the operating means for opening the door is aflush plate with a fingertip recess engageable only along one edge orre-entrant side of the recess which, by all logical means ofdetermination for opening operational action calls for pulling andpulling only. Nothing else is suggested or even implied.

Heretofore, flush type pull handle devices that responded to pull onlywere held closed by frictional grips, snaps or yieldable frictionallatches or frictionally yieldable latch keepers. Where bolts wereemployed to keep the door closed, prior devices of the flush type andpullto-open character, specially employed some visible means, sign orexpedient, in addition to the recess grip, to ndicate preliminaryprocedural action necessary prior to pulling, to open the door.

In the present invention with only a recess showing, normally theoperational procedure calls for only a pull, yet, upon normal physicalengagement for this purpose the shallow, scant linger-tip purchase orgrip of the recess is made purposely inadequate and the operatorsfingers begin to slip under pure pull upon the said side of the recess,whereupon, and almost immediately, an automatic reaction of increasedpurchase pressure of the finger tips upon the side of the recess, in adirection at right angles to the direction of pull is involuntarilyinduced while the pulling effort is still in force. The combination ofsuch pull and press is necessary, the latter being involuntarily inducedby the inadequacy of the former against a positively bolted closed door.As the purchase pressure is increased, the bolt become involuntaryundone and the concurrent pulling force, still in effect, is quiteSullicient to swing the now unbolted door, open.

From the closed position the initial pull is manifestly referred to asbeing in the forward direction, that is, at right angles to the plane ofthe door, and any involuntary yielding of the plate handle is referredto as ybeing in the transverse or lateral direction, in the plane of thedoor, or in a direction other than the direction of pull as initiallyapplied. l

With reference to the form of the invention shown in FIGS. l to 8, themechanism is applied in an accommodating manner to a pair of opposed,vertically hinged, panel doors disposed in a vertical plane in asuitable cabinet 10, ofV sheet metal construction. The front opening or"the cabinet is provided with a center post 12, forming openings 14,fitted with doors 15 and 16, hinged as at 17, and adapted to swingforwardly and outwardly as shown by the dot and dash lines in theirpartly open position as seen in FIG. l.

Along the inner edge and along the marginal boundary thereof, each ofthe doors is provided with a recessed escutcheonelike plate 18. Theseplates are adapted to lay at against the front face 20 of the paneldoors and to project therefrom only the barest minimum, which is nogreater than the thickness of the sheet metal of which the plate isfabricated. To further reduce the obtrusiveness of this plate, theperimetrical edges thereof as at Z2, are bevelled, thus providing inaddition, an easy-to-clean edge.

Referring to FIGS. 2 to 8, showing only the right hand door 16, theassociated recess plate 18, and its associated parts, the panel typedoor on which these parts are carried is of hollow construction andcomprised in part, mainly, of a front sheet 24, and a back sheet 26.These sheets are suitably `spaced from each other and between which,some of the mechanism and the bulge of the recess of the escutcheon-likeplate is disposed.

Integrally formed with the front sheet 24, is a rearwardly extendingportion 28, forming an edge wall for the panel, and through which, alatch-bolt 30 is adapted project. A lip-like ange 32, contiguous and atright angles to the edge wall 28, and integral therewith, is adapted toengage the rear wall or sheet 26, to form part of the enclosingstructure for the hollow panel type door. The bolting surface of thelatch-bolt 30, is designated as 34, and is disposed forward, in theplane parallel to the plane of the escutcheon plate 18. The latchingsurface 36, of the bolt 30, is rearwardly and angularly biased to theright as clearly seen in FIG. 3, so that during closing its inclinedlatching surface comes into camrned contact with the center post and iscaused to move inward to the right to a retracted position, as the panelmoves rearwardly to its final closed position. As will be more fullydescribed later, the latch-bolt is normally, yieldably retained in itsprojected position, outward of the edge wall 28, as shown is FIGS. 3 and5. At the final closed position of the door the latch-bolt 30 is causedto project into a hole 38, in the post 12 or into a suitable boltkeeper, thus placing the door in closed and bolt-locked condition.

It is therefore seen that the latch-bolt serves as a latch upon closingand as a positive locking bolt when the door is fully closed. Under suchcircumstances the door cannot be opened until the bolt is fullywithdrawn. However, there is nothing on the escutcheon plate to indicateor even suggest that a bolt is to be withdrawn before the door can beopened, yet, without this knowledge, actions incident or coincident withmere pulling will aftectuate the door opening, as will appear laterherein.

A finger engaging recess integrally formed in the escutcheon plate 18,is generally designated as 40, and is of recession depression character,substantially oblong in frontal appearance with rounded cove corners andwith rounded frontal edges that may come in contact with the fingers ofan operator. The recession depression per se, referred to herein as therecess 40, is depressed in the escutcheon plate in a biased or askewedmanner, that is, on the right hand door for example, the recess in theri ght hand plate skews from right to left as it extends rearwardly.Likewise, but in opposite hand manner, the recess in the left hand plateis skewed from left to right as it extends from front to the rear.Inwardly opposed gripping ledges are thus formed and disposed forengagement by respective hands of an operator. The recesses 40 aresubtantially shallow; so shallow that only tingertip grip orapplication, is had.

Referring now to FIG. 3, the recess 40 for the right hand is seen inplan section. The rear wall 42 of the recess is integrally formed withthe frame-like walls and front flanges 43. The recess 40 is ofsubstantially upright oblong formation and together with the side wallssurrounding the mouth of the recess, and the frame ilanges comprisingthe escutcheon plate 18. The upper and lower side walls 44, are paralleland join the front frame flanges to the rear wall 42 of the recess. Thevertical side wall portions 46 and 48 are substantially parallel and arebiased or askewed inwardly toward the edge 28 of the door. The said wallportion 46 is thus joined to the rear wall portion 42 by an acute covecorner portion 50, while the side wall portion 48 is joined to the rearwall portion 42 by an obtuse cove corner portion 52. At the front, theside wall portion 46 is joined to the front flange along the edge 52 ofacute formation. The side wall construction thus forms a re-entrantdeclining ledge adapted for engagement by the fingertips of the righthand for pulling upon the door. The linger contactable surface 48 of theside wall portion of the recess is unsuited for the purpose of applyinga pulling force upon the door toward opening inasmuch as this wallsurface is adversely inclined for attainment of finger purchase thereat.The upper and lower horizontally disposed wall surfaces 44 are alsounsuited for proper or sufficient finger purchase for applying a pullingforce upon the door. Such ledges do not suggest or invite their use fordoor opening pulling action. The only available side of the recess 40where pulling purchase is, and could be had, is behind the edge 54 andalong the re-entrant side wall 46, where a lingertip grip could be takenfor the purpose of exerting an intentional pull.

An opening 56 is provided in the front wall 24 of the door. This openingis slightly larger than the bulge formed by the recess 40 rearward ofthe escutcheon plate 18. Through this opening which is oblong inoutline, the bulge of the recess is adapted to swingingly move laterallyand freely, and only in a plane parallel to the front face of the door.The opening 56 is not visible from the front inasmuch as it is coveredcompletely by the continuous frame-like flanges surrounding the recessat the front surface of the escutcheon plate. Threaded studs 58 and 60are butt welded or otherwise secured to the rear of the escutcheon plate18, at the top and bottom anges thereof and substantially midwayhorizontally along these anges. These studs project rearwardly and passthrough respective holes 62 and 64 in the wall 24 of the door. The hole62, adapted to receive the stud 58, is of such size to closely yetfreely fit the stud. The hole 64 is substantially slotted as to permit alimited horizontal movement of the stud 60.

Elastic stop nuts 66 and bowed washers 68 thereunder are adapted intheir usual well known manner to keep the escutcheon plate frictionallybut lightly snug up against the front wall 24 of the door, withoutbinding or otherwise impeding the required operational movements abovementioned, as will be more fully explained hereinafter. The pair ofopposed and oppositely disposed recess plates 18 are made identical. Ininstallation at assembly the studs of one are inverted and inserted intothe holes 62 and 64 in a selectively opposed manner, so that a pair ofrecesses are askewed inwardly and toward each other for proper fingertipreception of the respective right and left hands.

The iingertip contactable or re-entrant surface of the said side wall 46of the recess is relatively steep and shallow, and the forcefulness ofthe grip is thus limited to, and naturally induces or auto-suggests,gentle pulling in continuous manner to elfectuate the opening of thedoor. Mere pulling however, is almost immediately felt to beinsutiicient as the fingertips feel their slippage. No amount of merepull could possibly produce any opening motion of the door that is heldclosed by a positively locked and bolted door. Therefore, andimmediately, almost instantaneously, even while the initial pullingmotion is still in progress, an automatic involuntary response ofincrease in lateral pressure is induced and naturally applied, toovercome this slippage, and to fortify the pulling effect of the actionsinitially intended, and applied.

This involuntary and induced increase of lateral pressure response isconcurrent with the pulling effort initially and solely intended untilall resistance to the bolts withdrawal is overcome, whereupon the etectof the initially applied action of mere pull becomes effective, thepulling energy being kinetically stored during the build-up of theinvoluntary lateral pressure.

As best seen in FIGS. 4 and 7, the latch-bolt is adapted to freely slidelongitudinally in a latch cage 70 which is adapted to be fixed as bywelding to a mounting plate 72. This mounting plate is adapted to bepositionally set with respect to the bolt keeper hole in the post 12. Inproper position at assembly the mounting plate 72 is spot welded inplace to the rear face of the front sheet of the door 24. A threadedstud 74 is end-butt welded to the plate 72 to project rearwardlytherefrom. This stud 74 is provided with a spacer nut member 76, awasher 78, and a lock nut 80, adapted to hold captive, the helicalportion of a wire hairpin type spring designated in general as 82. Thehelical portion of the spring surrounds the spacer nut 76, one free endof the spring is urged against the bulge of the recess 40 and againstthe outer surface of the reentrant side wall 46, while the other end ofthe hairpin spring is hooked around and urged against a pin 89 in a bellcrank 90, and urging the latch-bolt 30 and the escutcheon plate 18apart.

This bell crank lever 90 is pivotally mounted on the stud 74 and isprovided with a rearwardly projecting pin 92 adapted to pass freelythrough a slot 94 in a suitably bent front-plate element 96 forming partof the latch-bolt cage unit 70. A suitably bent and formed rear-plateelement 98 is adapted to be nestingly positioned and joined as by spotwelding to the front-plate element. This rearplate element 98 is adaptedas a tunnel-like drape around the latch-bolt pin 30 and, together withthe front-plate element 95 provides a slidable retaining means for thelatch-bolt 30. A hole 100, horizontally disposed in the latch-bolt 30 isadapted to receive the pin 92 of the bell crank with a free fit. Inassembled relationship as illustrated best in FIGS. and 7, it is seenthat the pin 92 is urged against the right end of the slot 94 thusprojecting the latch-bolt a predetermined distance, the amount ofprojection of the latch-bolt from the edge 28 of the door ispositionally determined by the setting of the mounting plate 72, whichis accommodated by the relatively adjustable disposition of theescutcheon plate and the yieldably accommodating disposition of the bellcrank. The hairpin spring urges the latch-bolt in one direction andprojecting from the edge 23 of the door and in a direction toward thekeeper post 12, and the escutcheon plate is urged in the direction awayfrom the center post or latch keeper as the case may be. It isunderstood that with a single door construction there will be no centerpost but only a keeper for the latch-bolt.

The latch-bolt end 192 of the bell crank lever is adapted to passbetween the bent back portion 104 of the frontplate element 96 (see FIG.7) and the mounting plate 72 along a cut-away portion 105 of the cageelegent 98. The other end of the bell crank overlies the opening 56 inthe front sheet 24 of the door and is, in normal position, in contact,or close to contact, With the rie-entrant wall 46 of the recess andalong bulge as indicated at 10S, and lies in the path of movement ofthis re-entrant wall as it swings on its pivot stud 5S. The motion atthe zones of contact of the end 108 and the wall 46 are chordallydifferent thereby creating a frictional sliding and resistance whichcontributes to the modular of increasing lateral involuntary pressurenecessary to cause withdrawal of the bolt upon opening.

In the above described form of the invention the sequence of actions andevents are most characteristically described as on the basis of theoperator being unfamiliar with the internal mechanism its performingactions and who proceeds in accordance with natural and logicalresponses and reactions. With intention to open the door, the approachto the closed door is with ordinary light contact of the fingertipsonly, which find grippable but shallow, purchase along the surface ofthe recess opposing the fingertips. After making such contact with thesurface of the recess along its re-entrantly inclined wall, the ensuingaction by the operator, is to pull in the forward direction. No forwardmovement of the door is accomplished but instead, a feeling of hindranceto the movement and slippage of the fingers, is manifest, to a degreedependent upon the locking components as well as the frictionalresistance set up by the pulling force in the forward direction againstan inclined surface in a direction other than forward. This inevitableslippage is naturally, automatically and involuntarily counteracted to,by increased pressure of the fingertips to prevent continued slippageand loss of fingertip purchase. This involuntary lateral pressureincrease is concurrently applied with the pulling effort as initiallyapplied together with increased or decreased pulling force in theforward direction. The pressure increase in the lateral direction isgradual and in response to natural reflex reaction. The lateral pressureis thus increased to the point where the recess plate yields laterallyand the 6 door quickly opens under the force of the forward pull whichis continually present as would naturally occur when all restraints aresuddenly removed.

Upon release of the grip the recess plate returns to its normal positionas shown in FIG. 4, as does the latch-bolt return to its projectedposition, all under the influence of the spring 82. In this normalcondition, to close the door, all that is required is to swing same inthe closing direction until the inclined surface of latch-bolt is camlatched past the post 12 or keeper plate (not shown) until the boltsprings into the keeper hole 3S, whereupon the door is positively boltlocked.

Gnce familiar with the working feel of the mechanism it can be operatedwith entirely voluntary and distinctly independent sequential actionsdeliberately applied, but the usually natural and convenient way to openthe door is as described.

In the form just described, a single bell crank and pivoted recess plateare employed. In the modication shown in FIGS. 9 and 10, two bell cranks110 and 112 are employed with a sliding escutcheon plate 114. The pins53 and 60 are slidably borne in slots 116 in the front sheet 24 of thedoor while the pin 92 of the latch-bolt is engaged by slots in the endsof the symmetrical but invertedly disposed bell cranks and 112.

In the previous forms described the latch-bolt is disposed within thelateral proximity of the escutcheon plate. In the modified form of theinvention shown in FIGS. 11 and 12, the latch-bolt 118 is remote fromthe lateral proximity of the recessed escutcheon plate 120 and anextension lever 122 is attached to the bulge of the recess as at 124 andis thus adapted to move about pivot on the aXis of the stud 125 which isadapted as the direct pivot f or the escutcheon plate 128.

Where the latch-bolt, preferably vertically located in the middle of thedoor edge, is to be disposed above or below the level of the escutcheonplate, such form as in FIGS. ll and l2 of the invention, provides suchspaced relationship. A hairpin type spring has one end fastened to a pin132 anchored in the front sheet 24 of the door while its other end isconnected to a pin 134 in the end of the latch-bolt 118. A slot 136 atthe end of the lever 122 hooks onto the pin 134 in the latch bolt. Thespring 130 urges the pin to bottom in the slot, thus causing theescutcheon plate to pivot counterclockwise up to where the end of theslot 138 coincides with the pin 60 in the normal position of themechanism as shown. The projected position of the latch-bolt isdetermined by the stopping engagement of the lever against the pin 132,under the influence of the spring 130.

While the invention has been shown and described as applied to a door ordoors in a vertical plane, with hinges disposed in the vertical andalong an edge opposite the latch-bolt edge, the hinges may be disposedalong an edge adjacent to the edge where the latch-bolt projects. Indoors that are inclined in planes other than vertical the term ofreference to pulling is in all cases in the direction normal to theplane of the door and the term of reference to the application ofinvoluntary increased lateral pressure is in or parallel to the plane ofthe door, and in the direction away from the hinge or hinges.

Having thus described the invention and its principles in severalembodiments, it is understood that other forms and modications thereofmay be had without departing from the spirit ofthe invention as embracedin the following claims.

I claim:

1. A hinged door of the character described having a flush type movabledoor-pulling plate-like member having a manually engageable door-pullingrecess at the front face thereof, a yieldably retractive latch-boltcarried by said door and operatively connected to said door pullingmember, said latch-bolt normally projecting edgewise from said door toengage means external of the door to hold same locked against pulling inthe direction normal to the plane of the plate-like member in closedposition of the door, said pulling recess extending rearwardly from thefront face of said door-pulling member and having an inclined sidesurface between said front and rear surfaces of said recess, saidinclined side surface sloping rearwardly and away from the hinged edgeof the door and being of such depth as to permit only fingertipengagement and of such inclination with respect to frictional purchaseof operating fingertips as to require sidewise pressure to attaineffective pulling purchase upon the closed and bolted door, whereby,upon manual contact and pressure sufficient for pulling purchase thesaid latch-bolt is first involuntarily withdrawn.

2. In a hinged door construction of the character described having arecessed type escutcheon plate only, visibly and presented and adaptedsolely for pulling purposes in the course of opening the door, thecombination of a normally projecting and yieldably retractive latch-boltcarried by the door and projecting from one lateral edge thereof,latch-bolt keeper means external of the door and adjacent said lateraledge and adapted to receive the latch. bolt in closed position of thedoor and to hold same in positively locked condition against pulling,and linkage means operatively connecting said escutcheon plate and said1atch-bolt whereby only lateral motion of the escutcheon plate istransmittable to the latch-bolt, said recess in said escutcheon plateextending rearwardly askewed and having a fingertip engaging surfacesloping rearwardly and away from the hinged edge of the door and of suchsteep inclination and affording such shallow fingertip purchase as toinduce the requirement of increasing lateral pressure to effectuatepulling results, whereby the escutcheon plate yields laterally,withdrawing the latch-bolt while the pulling force is still effectivelyapplied.

3. In a hinged door construction of the character described having onlya recessed flush type escutcheon plate visibly presented for pulling ina plane normal to the plane of the door, the combination of a yieldablyretractive latch-bolt carried by the door and projecting from an edgethereof other than the hinged edge of the door, latch-bolt keeper meansexternal of the door and adapted to receive the latch-bolt in closedposition of the door and to hold same in positively locked conditionagainst pulling open, and linkage means operatively connecting saidescutcheon plate and said latch-bolt whereby only lateral motion of theescutcheon is effective to withdraw the said latch-bolt, said lrecess insaid escutcheon plate extending rearwardly and eskewed and having aninclined fingertipengaging surface sloping rearwardly and away from thehinged edge of the door, said fingertip-engaging surface being of suchsteep inclination and affording such shallow fingertip purchase as torequire increasing lateral pressure against said fingertip-engagingsurface to avoid finger slippage during pulling attempts to open saidpositively locked door, whereby the escutcheon plate ultimately yieldsto said increasing pressure while pulling purchase is sought againstsaid inclined fingertip-engaging surface.

4. In a hinged door construction of the character described having onlya flush type escutcheon plate visible presented for pulling in a planenormal to the plane of the door, the combination of a yieldablyrefractive latchbolt carried by the door and projecting from an edgeother than the hinged edge of the door, latch-bolt keeper means externalof the door and adapted to receive the latch-bolt in closed position ofthe door and to hold same in a positively locked position againstpulling open, and linkage means operatively connecting said escutcheonplate and said latch-bolt whereby only lateral motion of the escutcheonyplate is effective to withdraw the said latch-bolt, said r recess insaid escutcheon plate extending rearwardly and askewed and having aninclined fingertip-engaging surface sloping rearwardly and toward anunhinged edge of the door, said fingertip-engaging surface being of suchsteep inclination and affording such shallow fingertip purchase as torequire increasing lateral pressure to maintain pulling purchase againstsaid positively locked door, whereby the escutcheon plate is caused toyield under said increasing pressure while pulling purchase andresulting pulling open of the door is eifectuated by the fingertips.

References Cited UNITED STATES PATENTS 2,153,827 4/1939 Ferris 292-1662,497,624 2/ 1950 Nelson 292-166 2,892,652 6/1959 Johnson 292-3363MARVIN A. CHAMPION, Primary Examiner.

EDWARD C. ALLEN, Examiner.

J. R. MOSES, Assistant Examiner.

1. A HINGED DOOR OF THE CHARACTER DESCRIBED HAVING A FLUSH TYPE MOVABLEDOOR-PULLING PLATE-LIKE MEMBER HAVING A MANUALLY ENGAGEABLE DOOR-PULLINGRECESS AT THE FRONT FACE THEREOF, A YIELDABLY RETRACTIVE LATCH-BOLTCARRIED BY SAID DOOR AND OPERATIVELY CONNECTED TO SAID DOOR PULLINGMEMBER, SAID LATCH-BOLT NORMALLY PROJECTING EDGEWISE FROM SAID DOOR TOENGAGE MEANS EXTERNAL OF THE DOOR TO HOLD SAME LOCKED AGAINST PULLING INTHE DIRECTION NORMAL TO THE PLANE OF THE PLATE-LIKE MEMBER IN CLOSEDPOSITION OF THE DOOR, SAID PULLING RECESS EXTENDING REARWARDLY FROM THEFRONT FACE OF SAID DOOR-PULLING MEMBER AND HAVING AN INCLINED SIDESURFACE BETWEEN SAID FRONT AND REAR SURFACES OF SAID RECESS, SAIDINCLINED SIDE SURFACES SLOPING REARWARDLY AND AWAY FROM THE HINGED EDGEOF THE DOOR AND BEING OF SUCH DEPTHS AS TO PERMIT ONLY FINGERTIPENGAGEMENT AND OF SUCH INCLINATION WITH RESPECT TO FRICTIONAL PURCHASEOF OPERATING FINGERTIPS AS TO REQUIRE SIDEWISE PRESSURE TO ATTAINEFFECTIVE PULLING PURCHASE UPON THE CLOSED AND BOLTED DOOR, WHEREBY,UPON MANUAL CONTACT AND PRESSURE SUFFICIENT FOR PULLING PURCHASE THESAID LATCH-BOLT IS FIRST INVOLUNTARILY WITHDRAWN.